From 2ea98fc39b21392c1556d6768604f54a578278d4 Mon Sep 17 00:00:00 2001
From: Matti Laakso <matti.laakso@outlook.com>
Date: Sun, 14 Jan 2018 17:39:53 +0200
Subject: [PATCH] ar71xx: fix 5 GHz Wi-Fi on NBG6716

Some NBG6716 do not have ath10k calibration data in flash, only in chip
OTP. To determine if flash has a valid calibration data, the first two
bytes telling the length of the calibration data are checked against the
requested length. If the lengths match, calibration data is valid and
read from flash.

Signed-off-by: Matti Laakso <matti.laakso@outlook.com>
---
 .../base-files/etc/hotplug.d/firmware/11-ath10k-caldata   | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/target/linux/ar71xx/base-files/etc/hotplug.d/firmware/11-ath10k-caldata b/target/linux/ar71xx/base-files/etc/hotplug.d/firmware/11-ath10k-caldata
index a3d4867b0b..e6ea873e40 100644
--- a/target/linux/ar71xx/base-files/etc/hotplug.d/firmware/11-ath10k-caldata
+++ b/target/linux/ar71xx/base-files/etc/hotplug.d/firmware/11-ath10k-caldata
@@ -18,12 +18,18 @@ ath10kcal_extract() {
 	local part=$1
 	local offset=$2
 	local count=$3
-	local mtd
+	local mtd cal_size
 
 	mtd=$(find_mtd_chardev $part)
 	[ -n "$mtd" ] || \
 		ath10kcal_die "no mtd device found for partition $part"
 
+	# Check that the calibration data size in header equals the desired size
+	cal_size=$(dd if=$mtd bs=2 count=1 skip=$(( $offset / 2 )) conv=swab 2>/dev/null | hexdump -ve '1/2 "%d"')
+
+	[ "$count" = "$cal_size" ] || \
+		ath10kcal_die "no calibration data found in $part"
+
 	dd if=$mtd of=/lib/firmware/$FIRMWARE bs=1 skip=$offset count=$count 2>/dev/null || \
 		ath10kcal_die "failed to extract calibration data from $mtd"
 }
-- 
2.30.2